In recent years, in wireless communication systems, compared with former communication systems with only telephone applications, higher wireless quality is demanded, and the transmitted power of a mobile station terminal is limited by such factors as the power supply capacity. It is therefore difficult to expand the wireless area covered by one wireless base station. Given this, a relay communication system in which a relay station is disposed at a far edge of the communication service area or in an area having poor radio signal coverage is used, with the object of expanding the communication service area and improving communication quality (for example, Patent Reference 1). In this relay communication system, relay communication is performed between a wireless base station and a mobile station terminal station, via a relay station.
In a wireless communication system between a base station and a mobile communication terminal (hereinafter referred to as “mobile station”) via a relay station, when judging whether communication is to be done by a transmission path between a mobile station and a base station or is to be done via a relay station, the following system has been known, in which evaluation values of each path are calculated from the information of the frequency band and transmission time to be used, the propagation loss value, the propagation loss variation width, the relative movement velocity, and the transmitted power value, and the path is calculated based on the evaluation values (refer, for example, to Patent Reference 2).
In LTE-A (Long Term Evolution-Advanced; Non-Patent Reference 1), a technique is under investigation in which transmission and reception are performed simultaneously, using a plurality of carriers (called component carriers) that are either continuous or discontinuous in frequency, thereby implementing communication that is both high-speed and high-capacity. In a base station device conforming to LTE-A, in order to maintain compatibility with 3.9-generation (LTE: Long Term Evolution) wireless communication systems, investigation is underway with regard to the division of a plurality of frequency band to be used in LTE-A into component carriers (for example, 20 MHz) for each frequency band of an older-generation wireless communication system. Investigation is also underway with regard to communicating using one of the component carriers to communicate with older-generation mobile stations and using the component carriers over a plurality of frequency bands to communicate with LTE-A mobile station devices, these being used simultaneously to communicate.